Remeron (mirtazapine) and Prozac (fluoxetine) are antidepressants used to treat depression. Remeron is also used to treat nausea, anxiety, posttraumatic stress syndrome, and as an appetite stimulant. Prozac is also used to treat bulimia, obsessive-compulsive disorder (OCD), panic disorder, and premenstrual dysphoric disorder (PMDD).